Subcategorization of Perineural Invasion Stratifies Oral Cavity Squamous Cell Carcinoma Prognosis.

Abstract

To evaluate whether subcategorization of perineural invasion (PNI) improves the prognostic resolution of the American Joint Committee on Cancer, Eighth Edition (AJCC8) staging system in oral cavity squamous cell carcinoma (OCSCC). OCSCC tumor specimens from patients seen at a tertiary care institution who underwent primary surgical resection between January 2019 and June 2021 were sorted into four PNI categories: negative, intratumoral, peripheral, and extratumoral. The prognostic effect of these PNI categories were assessed through Kaplan-Meier, Cox regression, and log-rank testing using recurrence-free survival (RFS) and overall survival (OS) as primary and secondary outcomes respectively. A total of 158 patients were examined. The median follow-up time was 21 months. PNI subcategorization further stratified RFS (p = 0.007) and OS (p = 0.002). Extratumoral PNI was associated with a 4.5-fold increase in recurrence risk (adjusted hazards ratio [aHR]: 4.53; 95% confidence interval [CI]: 1.1-18.66) and worse OS when compared with PNI negative disease (aHR: 5.71; 95% CI: 1.0-32.67). Peripheral PNI was associated with worse OS (aHR: 5.7; 95% CI: 1.35-24.08) but not worse RFS (p = 0.18) when compared with PNI negative disease. Interestingly, intratumoral PNI was not associated with significant differences in RFS (p = 0.087) or OS (p = 0.22) when compared with PNI negative disease. Subcategorization of OCSCC tumors into extratumoral, peripheral, and intratumoral PNI stratifies RFS and OS when compared with patients with PNI negative disease in an incremental fashion. This pilot study suggests that there may be added benefit in subcategorization of PNI in the prognostic evaluation of OCSCC. 4 Laryngoscope, 134:1656-1662, 2024.